Detergent and wear inhibiting mineral oil compositions



l l a l DETERGENT AND WEAR INHIBITING MINERAL OIL COMPOSITIONS John A. Edgar and Roland Frederick (Bergstrom, Martinez, and Robert C. Jones, Berkeley, Calif assignors to Shell Oil Company,*New York, .N. Y., a corporation of Delaware No Drawing. Filed Sept. 26, 1955,Ser.No. 536,746

4 Claims. (Cl. 252-40.7)

This invention relates to lubricating oil compositions and more particularly to highly detergent lubricating oil compositions which also possess good extreme pres- .sure properties and prevent wear.

Until recently, lubricating oil detergents or dispersants were generally the polyvalent metal salts or soaps of organic carboxylic acids, organic naphthenic acids or organic sulfonic acids. Detergents of this type although effective in engines operating at relatively high temperatures, they are ineffective at low temperatures such as are encountered in engines operating under severe, stopand-go, conditions.

As obviating some of the shortcomings of the metallic detergents it has been observed that certain oil-soluble non-ash synthetic polymeric compounds possess dispersant properties. Polymer compounds of this type range in molecular weight from about 1000 to about 1,000,- 000, and preferably from about 30,000 to about 500,000, and can be represented to consist essentially of units of the general formula:

R, R1 CHz(IJH-OH2CH X X1 2), wherein X can be the same or different polar group such as -r l-.o-N \N-N N; n.

is hyrogen or a short alkyl radical of not more than 4 carbon atoms and preferably an alkyl radical of from 1 to 3 carbon atoms; R can be the .same as R or a long alkyl radical of 8 or more carbon atoms and preferably from 14 to 18 carbon atoms or a basic group (CH N wherein n is an integer of 1 to 20 and preferablyof from 4 to 12, m can be zero or one; X; can be the same as XR or a long alkyl radical of at least 8 carbon atoms. At least oneof the Rs should be a long alkyl radical of at least 8 carbon atoms.

Although polymers of the type mentioned above and which will be described hereinafter in greater detail impart excellent detergency to lubricants used over wide temperature ranges, they lack the desired property of inhibiting wear which is encountered in various types of engines operating under low and high temperature conditions and under heavy loads and extreme pressures. A principal object of this invention is to produce a lubricating composition having excellent detergent or dispersant and anti-wear properties. Another object of this invention is to produce a lubricating composition suitable for use understop-and-go driving conditions.

These and other objects will be more fully understood and others w-ill be apparent fromthe description of the invention.

United States Patent 0 "ice It has now been discovered that the above and other objects can be attained by adding to a lubricating oil, a minor amount of an oil-soluble polar-containing polymeric detergent compound of the type mentioned above and represented by Formula I, and a minor amount of an oil-soluble metal carbocyclic carboxylate and preferably an oil-soluble highly basic metal organic carboxylate.

The imparting of anti-wear properties to non-ash containing polymeric detergents which lack this desired property, by metal organic carboxylates which, as is known to the art, normally function as detergents, is unusual. The manner or mechanism whereby this additive combination functions is not clearly understood, but the unusual manner in which these two additives act and the unexpected properties which they impart to oils are evidenced by the results of extensive tests.

The oil-soluble polymeric detergents as represented by the general Formula I can be characterized as polymers containing non-polar oil-solubilizing groups such as long chain alkyl radicals and polar active detergent groups of which preferred are the groups wherein R is hydrogen or a long chain alkyl radical, e.g., C C alkyl radical and R is a short alkyl radical of from 1 to 4 carbon atoms. It is pre- 'ferred that the non-polar oil-solubilizing group and the polar detergent group be attached either directly or indirectly to different carbon atoms of a long hydrocarbon backbone chain as indicated in Formula I.

One class of preferred polymeric compounds which can be used in accordance with the present invention are suitably prepared as hydrolyzed or alcoholized copolymers of alpha-olefinic hydrocarbons, such as alphaalkenes containing from 10 to about 40 carbon atoms, and preferably 12 to 30 carbon atoms with hydrolyzable vinyl compounds, such as vinyl halides (vinyl chloride) and vinyl esters (vinyl acetate) or as copolymers of such alpha-olefins with other low molecular weight polymerizable polar-substituted alpha-alkenes, such as the acrylo compounds, as illustrated by acrylic acid, acrylonitrile, acrylamide, methacrylic acid, methacrylonitrile, methacrylarnide, as well as mixtures and derivatives thereof. By alpha-olefinic hydrocarbons. is meant herein hydrocarbons which contain a terminal ethenyl (-CH=CH group. Polymeric compounds of this class can be represented by the general formula consisting essentially of units of a CHz-JJH-CHr-CH wherein R is a long alkyl radical which can be from 10 to 18 carbon atoms and Y can be Normally, the reactants are copolymerized in the presence of a catalyst. The catalyst suitable for use in making these polymers and copolymers include various oxygen-yielding catalysts, for example, various organic peroxides, such as aliphatic, aromatic, heterocyclic, and alicyclic peroxides such as diethyl peroxide, tertiary butyl hydroperoxide, dibenzoyl peroxide, dimethylthienyl peroxide, dicyclohexyl peroxide, dilauroyl peroxide, and urea peroxide. These are mentioned by way of nonlimiting examples of organic peroxides suitable for use in the preparation of additives for use in composiazodiisobutyronitn'le, etc. 7

Copolymers of this invention can be prepared by any :suitable means, such as described in U.S. Patents 2,421,-

971, and 2,467,774. They may also be produced by the method described in U.S. Patent 2,551,643, followed .by hydrolyzing the copolymer by the method described .in the first two patents. Suitable copolymers also can be prepared by the method described in U.S. Patents 2,421,971, and 2,467,774, except that for vinyl esters, acrylonitriles, acrylamides, or acrylic acids are used or these copolymers can be prepared by the general method described in U.S. Patents 2,436,926 and 2,486,241.

The following example illustrates suitable compounds and of their preparation:

EXAMPLE I Hydrolysis product of alpha octadece ne-vinyl acetate copolymer About 1 mole of vinyl acetate and 1.2 moles of alphan-octadecene were thoroughly mixed, a small amount of benzoyl peroxide was added to the mixture and the resulting mixture placed in a glass bomb from which air was displaced by nitrogen. The bomb was placed in a water bath maintained at around 80 C. for a period of about 24 hours. The product was topped to 170 C. at 2 mm. of Hg pressure and on analysis the residue had an ester value of 0.491 gram-equivalents of ester groups per 100 gramsof sample.

This product was alcoholized in about 1,800 m1. of methanol to which about 1 gram of metallic sodium was added. The mixture was distilled to remove the methyl acetate and the excess methanol and the product was then dispersed in heptane and topped. The resulting residue product was an alkanepolyol (polyhydric alkanol) having a molecular weight of about 8,000 as determined by light scattering means. From the molecular weight and the aforesaid number of gram equivalents of ester groups per 100 grams of the ester, it can be calculated that for the alkanepolyol there is a ratio of alcoholic hydroxyl groups to hydrocarbyl (hexadecyl) radicals of about 2.2. Furthermore, the average alkanepolyol molecule contains about 50 hydroxyethylene radicals and about 23 octadecylene-l,2-radicals; there is a total of a about 73 hydrocarbyl and hydroxyl radicals per molecule.

In other words, the molecule is a chain of 146 C-atoms having 50 hydroxyl and 23 hexadecyl radicals attached to 73 different C-atoms of the chain throughout the chain length. Those 73 C-atoms have attached thereto 73 H- atoms (one each) and the remainder of the C-atoms are saturated with 2 H-atoms each. The molecule can be represented by the formula:

Another class ofpolymeric detergents can be prepared by polymerizing unsaturated polymerizable heterocyclic nitrogen base compounds and derivatives thereof with another polymerizable unsaturated material free of heterocyclic nitrogen radicals, such as acrylic compounds, vinyl and vinylidine compounds, allyl compounds, or unsaturated polycarboxylic acids and the like. Polymers of this class can be represented by the general formula having units oif:

Z Z; (III) wherein Z is a basic heterocyclic nitrogen group such as a C-pyridyl radical, Z is an oil-solubilizing polar group,

is hydrogen or a short alkyl radical and R is an alkyl radical. V

The copolymers of this type can be prepared by any suitable means, the reaction preferably being carried out in the presence of a polymerization catalyst. Thus, the reactants in the mol ratio of 1:1 to 10:1 is preferably from 1:1 to 1:4 of a C-vinyl pyridine to other polymerizable material, e.g., acrylate can be reacted in the presence of from 0,1 to 5% of a catalyst such as a peroxide or azo compound in the presence or absence of an inert solvent such as a hydrocarbon under a blanket of nitrogen or carbon dioxide and at a temperature varying from room temperature or lower to about 180 C. or higher for a period of from about 2 to 48 hours until the average molecular weight of the copolymer exceeds 50,000 and preferably is within the range of from 75,000 to 700,000.

The following examples illustrate the preparation of polymeric compounds containing units of Formula III.

EXAMPLE II A mixture of about 1 mole of lauryl methacrylate, 1 mole of Z-methyl-S-vinyl pyridine and 0.4% wt. of

. benzoyl peroxide were placed in a suitable reaction vessel and the mixture reacted for a period of over 2 hours at 85 C. in a nitrogen atmosphere. The unreacted materials were stripped off at 185 C. and 1 mm. pressure and the resulting copolymer was a rubbery product containing around 3% nitrogen, having a molecular weight in excess of 150,000 and was soluble in hydrocarbon oils.

EXAMPLE HI v A copolymer of lauryl methacrylate and 2-methyl-5- vinyl pyridine was prepared by the method of Example II, but in which the mole ratio of the reactancts was 4 to 1 respectively. The nitrogen content of the product was about 2%, the molecular weight was in excess of 75,000 and it had a sticky rubbery consistency but was oil soluble.

Still another class of polymeric detergents can be represented by formula having repeating units:

carom-01124511,

wherein D is a polar radical such as I? C0 R1 where R is a long alkyl radical, e.g., C -C alkyl radical and E is a basic radical, e.g.,

is the same as in Formula III. Polymers of this type can be prepared by the methods described in U.S. Patents 2,584,968, 2,666,044, and 2,680,717, and include lauryl methacrylate/diethylamino ethyl methacrylate (:10) copolymer lauryl methacrylate/styrene/dibutylaminoethyl methacrylate, lauryl methacrylate/4-dimethylaminocyclohexyl methacrylamide (90/ 10), lauryl methacrylate/ tertoctylaminoethyl methacrylate, and mixtures thereof.

The second essential additive used in compositionsof this invention and which impart Wear inhibiting properties to said compositions is a polyvalent metal salt of a carbocyclic carboxylic acid and preferably being a basic polyvalent metal salt of an organic carboxylic acid, such as an aromatic carboxylic acid, such as a highly basic calcium, barium or, magnesium salts of a non-substituted or hydrocarbyl substituted benzoic, salicyclic, resorcylic, anthranilic, naphthoic acids illustrated specifically by basic calcium salts of Cg-Czg alkyl benzoic, C C alkyl salicyclic, naphthenic acids and mixtures thereof. Other basic polyvalent metal salts include the cycloaliphatic "carboxylates such as the basic calcium and barium naphthenates. The basicity of salts used in compositions of this invention can vary from 2% to 1000% and preferably from 50% to 800%. The neutral polyvalent metal salts of aromatic carboxylic acids are prepared by conventional means or are readily available commercially. The corresponding basic salts can be prepared by any suitable means such as the methods described in US. Patents 2,356,043, 2,409,687, 2,616,904, 2,616,905, and 2,616,910. The neutral and basic salts can include polyvalent metal salts such as the alkaline earth (Ca, Ba, Mg, or Sr) salts of benzoic, salicylic, C -C -alkyl salicylic, alkyl resorcylic, alkyl naphthoic, petroleum naphthenic acids, and mixtures thereof, of which preferred are the highly basic calcium and barium C -C -alky1 salicylate, alkyl benzoate and mixtures thereof.

To compositions of this invention can be added auxiliary additives such as anti-oxidants or corrosion inhibitors of which organic compounds containing inorganic phosphorus acidic radicals are particularly preferred. Compounds of this type can be obtained by reacting monoor polyhydroxy, or mercapto organic compounds, aliphatic olefins, e.g., isobutylene, cyclic olefins, e.g., terpenes, and mixtures thereof, with P POCl P 8 PSCI or P Se salts of said products are also included and are obtained by neutralizing the reaction products mentioned with oxides, hydroxides, carbonates, or halides of monoor polyvalent metals such as the alkali, alkaline earth or heavy metals exemplified by Na, K, Ca, Ba, Sr, Mg, A1, C0, Pb, Ni, and Fe, to form the corresponding salts and mixtures thereof. Compounds of this type include salts such as Na, Ca, Ba, Zn, and .Al salts of alkyl, alkaryl, aralkyl, cycloalkyl, aryl phosphates, thiophosphates, and specifically illustrated by Na,

.K, Ca, Ba, Zn, and Al salts of methylcyclohexyl phosphate, dimethyl cyclohexyl dithiophosphate, dihexyl acid thiophosphate, lauryl benzyl thiophosphate, butyl trichloromethanephosphonic acid; P S -olefin reaction product as described in US. Patents 2,316,080, 2,316,082, 2,316,086, 2,261,047, 2,540,084, 2,358,305, 2,466,408 2,344,393, 2,493,217, and 2,662,856, as well as the nonsalt or non-neutralized products such as P S -terpene re action products and mixtures thereof. Compounds of this type are available commercially under the trade names of Lubri-Zol 304 or 1060 (Lubri-Zol Corp.); Aerolube 70 (American Cyanamid Co.); Stan-Add 48 (Standard Oil Co. of Indiana) and Santolube 394C (Monsanto Chemical Go). Other phosphorus compounds Which can be used are of the type described by Smalheer et al. in Petroleum Processing, December 1952. A particularly preferred list of such compounds includes the Zn and Ba salts of dialkyl dithiophosphate, Na, K, and Ba salts of P S -polybutene reaction products and/ or P S -terpene (pinene) reaction products, said products being commercially available from Lubri-Zol Corporation, Standard Oil Company of Indiana, and Monsanto Chemical Company, respectively, under the trade names of Lubri-Zol 304 and Lubri-Zol 1060, Stan-Add 47, 48, and L-9103, and Santolube 394-C.

Lubricating oils for additives of this invention can be any natural or synthetic material having lubricating properties. Thus, the base may be a hydrocarbon oil of wide viscosity range, e.g., 100 SUS at 100 F. to 150 SUS at 210 F. The hydrocarbon oils may be blended with fixed oils such as castor oil, lard oil, and the like, and/or with synthetic lubricants such as polymerized olefins, copolymers of alkylene glycols, and oxides; organic esters of polybasic organic, and inorganic acids, e.g., di-2-ethylhexyl sebacate, dioctyl phthalate, thioctyl phosphate, polymeric tetrahydrofuran, polyalkyl silicone polymers, e.g., dimethyl silicone polymer, and the like. If desired, the synthetic lubricants may be used as the sole base lubricant or admixed with fixed oils and their derivatives.

Mineral lubricating oils which are particularly desirable for use in compositions of this invention and which have been used as a base for the compositions of this invention "wereobtained from West Texas Ellenburger crudes, East Texas crudes, Oklahoma ,crudes, California crudes, and a refined oil therefrom, had the following properties:

Gravity, API Min. 26.5 Pour point, F Max. 1 0 Flash, COC, F Min. 390 Viscosity, SUS at F Viscosity index Min. 95

Another such oil is an SAE 30 mineral oil having the following properties:

Gravity, API Min. 24.5 Pour point, F Max. 5 Flash, COC, F Min. 415 Viscosity, SUS at 210 F 58-63 Viscosity index 50-60 The general formulation of compositions of this invention can be represented by:

Preferred compositions of this invention are illustrated by the following compositions:

COMPOSITION A Copolymer of Lauryl methacrylate/diethylamino ethyl methacrylate (90:10) 5% wt.

Basic calcium C alkyl salicylate 0.5% Sulfate residue. Zn dimethyl cyclohexyl thio-,

phosphate 0.8% Wt. Mineral lubricating oil (SAE 30) Balance.

COMPOSITION B Cop olymer of Lauryl methacrylate/ 2-rnethyl-5-vinylpyridine 2% wt.

Basic calcium Chg-C1 alkyl salicylate 2% wt.

Mineral lubricating oil Balance.

COMPOSITION C Hydrolyzed copolymer of Octadecene-l/vinyl acetate 2%.

Basic calcium C -C alkyl salicylate 2% Mineral lubricating oil Balance.

COMPOSITION D Copolymer of Octadecyl methacrylate/ 2 methyl-S-vinyl pyridine (4:1) 2% wt.

Basic Calcium C C alkyl salicylate 2% wt. Mineral lubricating oil Balance.

COMPOSITION E Copolymer of Lauryl methacrylate/ d-iethylamino alkyl methacrylate Basic Ca naphthenate 0.5 Sulfate residue. Zn dimethyl cyclohexyl thiophosphate 0.8% wt. Mineral lubricating oil (SAE 30) Balance.

' Other examples of compositions of this invention include mineral lubricating oils of the SAE 10, 20, 30, or IOW -30type containing from about 1% to 6% by weight of copo'lymers of lauryl methacrylate/styrene/dibutylamino. ethyl methacrylate, lauryl methacrylate/4-dimethylamino-cyclohexyl methacrylamide, lauryl methacfylate/Z-methyl-S-vinyl pyridine, lauryl methacrylate/ 2-ethyl-5-vinyl pyridine, lauryl mechacrylamide/2-methyl- -vinyl pyridine, hydrolyzed copolymer of hexadecene-l/ vinyl acetate, and mixtures thereof, and from about 0.5% to about 5% by weight of neutral and/ or basic calcium,

barium, or zinc alltyl salicylate, alkyl benzoate and mixtures thereof. To any 01': these compositions can be added in amounts of from about 0.1% to about 1% other additives such as metal dithiophosphates (Zn alkyl dithiophosphate) metal dialkyl dithiocarbamates (Zn dibutyl dithiocai'bamate) amines such as phenyl-a-naphthyl-r 'amine, octadecylamine, viscosity index irnprovers and pour point depressants such as the, Acryloids, and specifically, Acryloid, 150, 618, 710, and/or 768, made by Rohm and Hass and described in US. Patent 2,710,842; condensation products of chlorinated parafiin wax and naphthalene; extreme pressure agents such as amine salts of trichlorornethane phosphonic acid, its ester,

amides or amine salts; thereof.

The outstanding properties of composition of this inorganic sulfides and mixturesyention were demonstrated when Composition A was tested in a Chevrolet engine under EX-3 test procedure and at the end of the test the engine was clean, no sign of wear or corrosion was noted, no piston rings were stuck, and the engine was in excellent condition. On the 5 other hand, when the basic calcium C alkyl salicylate was omitted from Composition A (identified as Composition X) and tested under equivalent conditions the engine was in poor condition as exhibited by several stuck rings and considerable wear of engine parts was evidenced.

Similar results as with Composition A can be obtained with Compositions B, C, D, or E, or other compositions of this invention in the EX-3 engine test procedure.

Compositions of this invention can be used as engine oils, turbine oils, gear oils, and various other fields of lubrication where detergency and wear inhibiting properties are essential.

We claim as our invention:

1. A lubricating oil composition comprising a major amount of mineral lubricating oil and a minor but detergent amount of an oil-soluble -copolym'er of anacrylate esterof an acrylic acid and a long chain aliphatic alcohol and a vinyl pyridine in the m'ol ratio of 1:1to 10:1 respectively and having a molecular weight of from 50,000 to 700,000 and a minor, but went inhibiting amount of an oil-soluble basic alkaline earth metal aromatic carboxylate'.

'2. A lubricating oil composition comprising a major amount of mineral lubricating oil anda minor but detergent amount of an oil-soluble copolymer of lauryl methacrylate and a vinyl-pyridine in the mol ratio of 1:1 to 10:1 respectively and having a molecular weight of from 50,000 to 700,000 and a minor but wear inhibiting amount of an oil-soluble basic alkaline earth metal salicylate.

3. A lubricating oil composition comprising a major amount of mineral lubricating oil and a minor but detergent amount of an oil-soluble copolymer of lauryl methacrylate and 2-methyl-5-vinyl pyridine in the mol ratio of 1:1 to 10:1 respectively and having a molecular Weight of from 50,000 to 700,000 and a minor but wear inhibiting amount of an oil-soluble basic calcium salicylate.

4. A lubricating oil composition comprising a-major amount of mineral lubricating oil and a minor but detergent amount of an oil-soluble copolymer of octadecyl methacrylate and 2-methyl-5-vinyl pyridine in the mol ratio of 1:1 to 10:1 respectively and having a molecular weight of from 50,000 to 700,000 and a minor but wear inhibiting amount of an oil-soluble basic calcium salicylate.

References Cited the file of this patent' UNITED STATES PATENTS OTHER REFERENCES A New Class of Polymeric Dispersants for Hydrocarbon Systems, presented at Amer. Chem. Soc. Meet, Kansas City, Mo., March 23 to April 1, 1954, 5 pages, 

1. A LUBRICATING OIL COMPOSITION COMPRISING A MAJOR AMOUNT OF MINERAL LUBRICATING OIL AND A MINOR BUT DETERGENT AMOUNT OF AN OIL-SOLUBLE COPOLYMER OF AN ACRYLATE ESTER OF AN ACRYLIC ACID AND A LONG CHAIN ALIPHATIC ALCOHOL AND A VINYL PYRIDINE IN THE MOL RATIO OF 1:1 TO 10:1 RESPECTIVELY AND HAVING A MOLECULAR WEIGHT OF FROM 50,000 TO 700,000 AND A MINOR, BUT WEAR INHIBITING AMOUNT OF AN OIL-SOLUBLE BASIC ALKALINE EARTH METAL AROMATIC CARBOXYLATE. 